Continuous-Flow Anaerobic Digester to Convert Organic Waste Material into Biogas

Processes Feedstock Waste into Renewable Energy

This two-phase anaerobic digester uses two connected vessels to facilitate continuous digestion of organic materials to produce biogas. Most available anaerobic digesters are classified as single-phase, dual-phase, or batch, have a number of problems that limit efficiency. Single-phase anaerobic digesters offer little control over the digestion process and often produce less biogas due to competing microorganisms. Batch anaerobic digesters can emit odors and biogas but output is not continuous. Available two-phase anaerobic digesters produce biogas in only one vessel, requiring acidogenic bacteria and heating, which makes this a more costly system. Additionally, both single-phase and batch digesters suffer from foaming, wherein biogas is trapped in fine bubbles on the surface of the waste, resulting in lower production of biogas.

Researchers at the University of Florida have developed a two-phase anaerobic digester that continually produces biogas, does not require acidogenic bacteria, and does not require heating. This digester separates solids and liquids into two sealable reactors, offering a more controllable environment to inhibit foaming and a more efficient anaerobic digestion process for continuous biogas production.

Application

Anaerobic digestion of organic waste for continuous biogas production

Advantages

• Takes in organic waste streams continuously and segregates the solid and liquid waste into separately sealed reactors for simultaneous anaerobic digestion, providing continuous and more efficient biogas production
• Handles multiple feedstocks at once, digesting the organic material and producing the biogas in a much shorter timeframe
• Is low-maintenance, odorless and scalable, enabling a business to match waste disposal or energy production processes to their needs

Technology

This anaerobic digestion system uses two reactors that operate in parallel to continuously process the solid and liquid portions of organic waste streams into biogas. The digester intakes biomass streams and separates the solids and liquids into separate reactors, both of which utilize anaerobic digestion to convert the waste into biogas. Unlike available anaerobic digesters, this system can produce biogas consistently and continuously, allowing for regular or continuous loading without disturbing the flow of digestion inside the reactors.